关于使用JS前台加密、JAVA后台解密的RSA实现，RSA加密和签名

需求环境：

西安项目中，客户要求保护用户的密码信息，不允许在http中传递明文的密码信息。

实现：

用RSA非对称加密方式实现。后台生成rsa密钥对，然后在登陆页面设置rsa公钥，提交时用公钥加密密码，生成的密文传到后台，用私钥解密，获取密码明文。

这样客户端只需要知道rsa加密方式和公钥，前台不知道私钥是无法解密的，此解决方案还是相对比较安全的。

附件是参照网友资料的Java+JS的实现，放在这里供大家下载。访问方式/RSA/login.jsp。

需要到http://www.bouncycastle.org下载bcprov-jdk14-123.jar文件。

因为后台要转换成bigint，所以对明文长度有些限制：

总长度不超过126（1汉字长度为9），如下两个字符串：

阿送大法散得阿送大法散得阿送

1232132131231231232131232K1232132131231231232131232K1232132131231231232131232K1232132131231231232131232K1234567890123456789012

RSA速度

* 由于进行的都是大数计算，使得RSA最快的情况也比DES慢上100倍，无论 是软件还是硬件实现。

* 速度一直是RSA的缺陷。一般来说只用于少量数据 加密。

Util.java

Java代码


package RSA;

/**

*

*/

import java.io.ByteArrayOutputStream;

import java.io.FileInputStream;

import java.io.FileOutputStream;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.math.BigInteger;

import java.security.KeyFactory;

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.NoSuchAlgorithmException;

import java.security.PrivateKey;

import java.security.PublicKey;

import java.security.SecureRandom;

import java.security.interfaces.RSAPrivateKey;

import java.security.interfaces.RSAPublicKey;

import java.security.spec.InvalidKeySpecException;

import java.security.spec.RSAPrivateKeySpec;

import java.security.spec.RSAPublicKeySpec;

import javax.crypto.Cipher;

/**

* RSA 工具类。提供加密，解密，生成密钥对等方法。

* 需要到http://www.bouncycastle.org下载bcprov-jdk14-123.jar。

*

*/

public class RSAUtil {

private static String RSAKeyStore = "C:/RSAKey.txt";

/**

* * 生成密钥对 *

*

* @return KeyPair *

* @throws EncryptException

*/

public static KeyPair generateKeyPair() throws Exception {

try {

KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA",

new org.bouncycastle.jce.provider.BouncyCastleProvider());

final int KEY_SIZE = 1024;// 没什么好说的了，这个值关系到块加密的大小，可以更改，但是不要太大，否则效率会低

keyPairGen.initialize(KEY_SIZE, new SecureRandom());

KeyPair keyPair = keyPairGen.generateKeyPair();

System.out.println(keyPair.getPrivate());

System.out.println(keyPair.getPublic());

saveKeyPair(keyPair);

return keyPair;

} catch (Exception e) {

throw new Exception(e.getMessage());

}

}

public static KeyPair getKeyPair() throws Exception {

FileInputStream fis = new FileInputStream(RSAKeyStore);

ObjectInputStream oos = new ObjectInputStream(fis);

KeyPair kp = (KeyPair) oos.readObject();

oos.close();

fis.close();

return kp;

}

public static void saveKeyPair(KeyPair kp) throws Exception {

FileOutputStream fos = new FileOutputStream(RSAKeyStore);

ObjectOutputStream oos = new ObjectOutputStream(fos);

// 生成密钥

oos.writeObject(kp);

oos.close();

fos.close();

}

/**

* * 生成公钥 *

*

* @param modulus *

* @param publicExponent *

* @return RSAPublicKey *

* @throws Exception

*/

public static RSAPublicKey generateRSAPublicKey(byte[] modulus,

byte[] publicExponent) throws Exception {

KeyFactory keyFac = null;

try {

keyFac = KeyFactory.getInstance("RSA",

new org.bouncycastle.jce.provider.BouncyCastleProvider());

} catch (NoSuchAlgorithmException ex) {

throw new Exception(ex.getMessage());

}

RSAPublicKeySpec pubKeySpec = new RSAPublicKeySpec(new BigInteger(

modulus), new BigInteger(publicExponent));

try {

return (RSAPublicKey) keyFac.generatePublic(pubKeySpec);

} catch (InvalidKeySpecException ex) {

throw new Exception(ex.getMessage());

}

}

/**

* * 生成私钥 *

*

* @param modulus *

* @param privateExponent *

* @return RSAPrivateKey *

* @throws Exception

*/

public static RSAPrivateKey generateRSAPrivateKey(byte[] modulus,

byte[] privateExponent) throws Exception {

KeyFactory keyFac = null;

try {

keyFac = KeyFactory.getInstance("RSA",

new org.bouncycastle.jce.provider.BouncyCastleProvider());

} catch (NoSuchAlgorithmException ex) {

throw new Exception(ex.getMessage());

}

RSAPrivateKeySpec priKeySpec = new RSAPrivateKeySpec(new BigInteger(

modulus), new BigInteger(privateExponent));

try {

return (RSAPrivateKey) keyFac.generatePrivate(priKeySpec);

} catch (InvalidKeySpecException ex) {

throw new Exception(ex.getMessage());

}

}

/**

* * 加密 *

*

* @param key

* 加密的密钥 *

* @param data

* 待加密的明文数据 *

* @return 加密后的数据 *

* @throws Exception

*/

public static byte[] encrypt(PublicKey pk, byte[] data) throws Exception {

try {

Cipher cipher = Cipher.getInstance("RSA",

new org.bouncycastle.jce.provider.BouncyCastleProvider());

cipher.init(Cipher.ENCRYPT_MODE, pk);

int blockSize = cipher.getBlockSize();// 获得加密块大小，如：加密前数据为128个byte，而key_size=1024

// 加密块大小为127

// byte,加密后为128个byte;因此共有2个加密块，第一个127

// byte第二个为1个byte

int outputSize = cipher.getOutputSize(data.length);// 获得加密块加密后块大小

int leavedSize = data.length % blockSize;

int blocksSize = leavedSize != 0 ? data.length / blockSize + 1

: data.length / blockSize;

byte[] raw = new byte[outputSize * blocksSize];

int i = 0;

while (data.length - i * blockSize > 0) {

if (data.length - i * blockSize > blockSize)

cipher.doFinal(data, i * blockSize, blockSize, raw, i

* outputSize);

else

cipher.doFinal(data, i * blockSize, data.length - i

* blockSize, raw, i * outputSize);

// 这里面doUpdate方法不可用，查看源代码后发现每次doUpdate后并没有什么实际动作除了把byte[]放到

// ByteArrayOutputStream中，而最后doFinal的时候才将所有的byte[]进行加密，可是到了此时加密块大小很可能已经超出了

// OutputSize所以只好用dofinal方法。

i++;

}

return raw;

} catch (Exception e) {

throw new Exception(e.getMessage());

}

}

/**

* * 解密 *

*

* @param key

* 解密的密钥 *

* @param raw

* 已经加密的数据 *

* @return 解密后的明文 *

* @throws Exception

*/

public static byte[] decrypt(PrivateKey pk, byte[] raw) throws Exception {

try {

Cipher cipher = Cipher.getInstance("RSA",

new org.bouncycastle.jce.provider.BouncyCastleProvider());

cipher.init(cipher.DECRYPT_MODE, pk);

int blockSize = cipher.getBlockSize();

ByteArrayOutputStream bout = new ByteArrayOutputStream(64);

int j = 0;

while (raw.length - j * blockSize > 0) {

bout.write(cipher.doFinal(raw, j * blockSize, blockSize));

j++;

}

return bout.toByteArray();

} catch (Exception e) {

throw new Exception(e.getMessage());

}

}

/**

* * *

*

* @param args *

* @throws Exception

*/

public static void main(String[] args) throws Exception {

RSAPublicKey rsap = (RSAPublicKey) RSAUtil.generateKeyPair().getPublic();

String test = "hello world";

byte[] en_test = encrypt(getKeyPair().getPublic(), test.getBytes());

byte[] de_test = decrypt(getKeyPair().getPrivate(), en_test);

System.out.println(new String(de_test));

}

}

LoginAction.java

Java代码


package RSA;

//login

/*

* Generated by MyEclipse Struts

* Template path: templates/java/JavaClass.vtl

*/

import java.math.BigInteger;

import java.net.URLDecoder;

import java.net.URLEncoder;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import RSA.RSAUtil;

/**

* MyEclipse Struts Creation date: 06-28-2008

*

* XDoclet definition:

*

* @struts.action path="/login" name="loginForm" input="/login.jsp"

* scope="request" validate="true"

* @struts.action-forward name="error" path="/error.jsp"

* @struts.action-forward name="success" path="/success.jsp"

*/

public class LoginAction {

/*

* Generated Methods

*/

/**

* Method execute

*

* @param mapping

* @param form

* @param request

* @param response

* @return ActionForward

*/

public boolean execute(HttpServletRequest request,

HttpServletResponse response) throws Exception {

String pwd ;

String result = request.getParameter("result");

System.out.println("原文加密后为：");

System.out.println(result);

byte[] en_result = new BigInteger(result, 16).toByteArray();

//System.out.println("转成byte[]" + new String(en_result));

byte[] de_result = RSAUtil.decrypt(RSAUtil.getKeyPair().getPrivate(),

en_result);

System.out.println("还原密文：");

System.out.println(new String(de_result));

StringBuffer sb = new StringBuffer();

sb.append(new String(de_result));

pwd = sb.reverse().toString();

System.out.println(sb);

System.out.println("=================================");

pwd = URLDecoder.decode(pwd,"UTF-8");//

System.out.println(pwd);

request.setAttribute("pwd", pwd);

return true;

}

}

登陆login.jsp

Html代码


<%@ page language="java" pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<html:html lang="true">

<head>

<title>login</title>

<script type="text/javascript" src="js/RSA.js"></script>

<script type="text/javascript" src="js/BigInt.js"></script>

<script type="text/javascript" src="js/Barrett.js"></script>

<script type="text/javascript">

function rsalogin(){

var thisPwd = document.getElementById("password").value;

bodyRSA();

var result = encryptedString(key, encodeURIComponent(thisPwd));

//alert(encodeURIComponent(thisPwd)+"\r\n"+result);

loginForm.action="loginCHK.jsp?result="+result;

loginForm.submit();

}

var key ;

function bodyRSA(){

setMaxDigits(130);

key = new RSAKeyPair("10001","","8246a46f44fc4d961e139fd70f4787d272d374532f4d2d9b7cbaad6a15a8c1301319aa6b3f30413b859351c71938aec516fa7147b69168b195e81df46b6bed7950cf3a1c719d42175f73d7c97a85d7d20a9e83688b92f05b3059bb2ff75cd7190a042cd2db97ebc2ab4da366f2a7085556ed613b5a39c9fdd2bb2595d1dc23b5");

}

</script>

</head>

<body>

<form method="post" name="loginForm" target=_blank>

<table border="0">

<tr>

<td>

Password:

</td>

<td>

<input type='text' name="password" id=password style='width:400px' value="my passwd"/>

</td>

</tr>

<tr>

<td colspan="2" align="center">

<input type="button" value="SUBMIT" onclick="rsalogin();" />

</td>

</tr>

</table>

</form>

</body>

</html:html>

登陆校验loginCHK.jsp

Html代码


<%@ page language="java" pageEncoding="UTF-8" contentType="text/html; charset=UTF-8"%>

<jsp:directive.page import="RSA.LoginAction"/>

<%

LoginAction la = new LoginAction();

la.execute(request ,response);

%>

pwd is [<%=request.getAttribute("pwd")%>]

================================================

另外，通过RSA还可以实现数字签名 ：用私钥签名、公钥验证即可。具体可以看代码：

Java代码


package encode;

import java.security.KeyPair;

import java.security.KeyPairGenerator;

import java.security.Signature;

public class DigitalSignature2Example {

public static void main(String[] args) {

args = new String[] { "中国" };

if (args.length != 1) {

System.err.println("Usage:java DigitalSignature2Example ");

System.exit(1);

}

try {

byte[] plainText = args[0].getBytes("UTF-8");

System.out.println("\nStart generating RSA key.");

// 生成RSA密钥对

KeyPairGenerator keyGen = KeyPairGenerator.getInstance("RSA");

// 初始化密钥长度

keyGen.initialize(1024);

// 生成密钥对

KeyPair pair = keyGen.generateKeyPair();

System.out.println("\nFinish generating RSA key.");

// 使用私钥签名

Signature sig = Signature.getInstance("SHA1WithRSA");

// 用指定的私钥进行初始化

sig.initSign(pair.getPrivate());

// 添加要签名的信息

sig.update(plainText);

// 返回签名的字节数组

byte[] signature = sig.sign();

System.out.println(sig.getProvider().getInfo());

System.out.println("\nSignature: ");

System.out.println(new String(signature, "UTF-8"));

// 使用公钥验证

System.out.println("\nStart signature verification.");

sig.initVerify(pair.getPublic());

// 添加要验证的信息

sig.update(plainText);

if (sig.verify(signature)) {

System.out.println("Signature verificated.");

} else {

System.out.println("Signature failed.");

}

} catch (Exception e) {

e.printStackTrace();

}

}

}